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#195763 - 08/20/10 02:18 PM Phase Convertor Sizing
Yoopersup Offline

Registered: 03/04/03
Posts: 826
Loc: Michigan
MCA 74 on compressor unit (all mts taken into account).
240 v single phase to 240 v 3 phase.
40 hp convertor .
input Aprox 127 amps
outputaprox 100 amps.

2014 / 2011 NEC & Related Books and Study Guides
#195777 - 08/22/10 01:10 AM Re: Phase Convertor Sizing [Re: Yoopersup]
twh Offline

Registered: 03/11/04
Posts: 895
Loc: Regina, Sask.
I'm guessing you're looking at a rotary converter. Do the motors need to be de-rated? The math looks off between single phase input and 3 phase output.

#195779 - 08/22/10 10:15 AM Re: Phase Convertor Sizing [Re: twh]
Tom Offline

Registered: 01/01/01
Posts: 1069
Loc: Shinnston, WV USA
Any chance of doing this with VFD's? Appropriately sized VFD's can convert a single phase input to three phase.
Few things are harder to put up with than the annoyance of a good example.

#195780 - 08/22/10 12:18 PM Re: Phase Convertor Sizing [Re: Tom]
Yoopersup Offline

Registered: 03/04/03
Posts: 826
Loc: Michigan
This is a Full HVAC unit was ordered wrong. MCA on name plate 74 amps single point hookup.
So need about 80 amps or so on three phase side.
As starteres ect are all ready in the package looking for 3 phase power imput. Vendor told us 40 hp unit well do the trick just checking.


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